Beam layout optimisation

Abstract

A beam layout is optimised for a given traffic distribution and network state by determining optimum beam centre positions and generating a beam layout so as to meet system requirements and minimise the distances of locations within a coverage area from the optimum beam centre positions. Adjacent beams in low traffic areas may be merged.

The invention claimed is: 
     
         1 . A method of generating an optimized beam layout for a satellite in a satellite communications system, the method comprising:
 a. receiving terminal and/or network data representing a distribution of communications terminals to be served by the satellite in the coverage area;   b. optimizing the positions of a set of beam centers with respect to the terminal and/or network data, to generate optimized beam center positions;   c. deriving an optimized beam layout from the optimized beam center positions;   d. merging one or more adjacent beams in the optimized beam layout to generate merged optimized beam layout data, wherein the merged adjacent beams correspond to areas of low traffic; and   e. outputting the merged beam layout data,   wherein the method includes identifying one or more high traffic or high priority terminals from the terminal and/or network data and determining an overlay beam directed to the one or more high traffic terminals, and   wherein the traffic from the one or more high traffic or high priority terminals is removed from consideration of the optimized beam layout.   
     
     
         2 . The method of  claim 1 , wherein the terminal and/or network data is represented by a density function. 
     
     
         3 . The method of  claim 1 , wherein the step of optimizing the positions of the beam centers comprises minimizing a function. 
     
     
         4 . The method of  claim 3 , wherein the function represents an attraction of the beam centers to regions of high parameter density. 
     
     
         5 . The method of  claim 3 , wherein the function represents one or more constraints in the spacing between the beam centers. 
     
     
         6 . The method of  claim 3 , wherein the function represents one or more constraints on distance of each beam center from a previous position. 
     
     
         7 . The method of  claim 3 , wherein the function represents containment of the beam centers within a given coverage area. 
     
     
         8 . The method of  claim 3 , wherein minimizing the function includes ensuring a global or near-global minimum. 
     
     
         9 . The method of  claim 3 , wherein the function is a scalar function. 
     
     
         10 . The method of  claim 1 , wherein the optimized beam layout data is derived from the optimized beam center positions so as to minimize the distance of locations within the coverage area from the optimized beam centers. 
     
     
         11 . The method of  claim 1 , wherein merging the one or more adjacent beams includes simplifying the geometry of the optimized beam layout. 
     
     
         12 . The method of  claim 1 , including quantizing the optimized beam layout. 
     
     
         13 . The method of  claim 1 , comprising iteratively performing the method steps of a. through e., wherein the terminal and/or network data varies with time. 
     
     
         14 . A method of generating an optimized beam layout for a satellite in a satellite communications system, the method comprising:
 a. receiving terminal and/or network data representing a distribution of communications terminals to be served by the satellite in the coverage area;   b. optimizing the positions of a set of beam centers with respect to the terminal and/or network data, to generate optimized beam center positions;   c. deriving an optimized beam layout from the optimized beam center positions;   d. merging one or more adjacent beams in the optimized beam layout to generate merged optimized bean layout data, wherein the merged adjacent beams correspond to areas of low traffic; and   e. outputting the merged beam layout data,   wherein the method includes synthesizing a set of beam weights to match or approximate the optimized beam layout.   
     
     
         15 . The method of  claim 14 , wherein the terminal and/or network data is represented by a density function. 
     
     
         16 . The method of  claim 14 , wherein the step of optimizing the positions of the beam centers comprises minimizing a function. 
     
     
         17 . The method of  claim 16 , wherein the function represents an attraction of the beam centers to regions of high parameter density. 
     
     
         18 . The method of  claim 16 , wherein the function represents one or more constraints in the spacing between the beam centers. 
     
     
         19 . The method of  claim 16 , wherein the function represents one or more constraints on distance of each beam center from a previous positon. 
     
     
         20 . The method of  claim 16 , wherein the function represents containment of the beam centers within a given coverage area. 
     
     
         21 . The method of  claim 16 , wherein minimizing the function includes ensuring a global or near-global minimum. 
     
     
         22 . The method of  claim 16 , wherein the function is a scalar function. 
     
     
         23 . The method of  claim 14 , wherein the optimized beam layout data is derived from the optimized beam center positions so as to minimize the distance of locations within the coverage area from the optimized beam centers. 
     
     
         24 . The method of  claim 14 , wherein merging the one or more adjacent beams includes simplifying the geometry of the optimized beam layout. 
     
     
         25 . The method of  claim 14 , including identifying one or more high traffic or high priority terminals from the terminal and/or network data and determining an overlay beam directed to the one or more high traffic terminals. 
     
     
         26 . The method of  claim 25 , wherein the traffic from the one or more high traffic or high priority terminals is removed from consideration of the optimized beam layout. 
     
     
         27 . The method of  claim 14 , including quantizing the optimized beam layout. 
     
     
         28 . The method of  claim 14 , comprising iteratively performing the method steps of a. through e., wherein the terminal and/or network data varies with time.